New Amide-type Liquid Crystal Crown Ether Ligands And Complexes Synthesis And Characterization

The dissertation consists of four parts.1. PrefaceThe discover, basic concept, chymistry structure, classification and characterization of liquid crystal, crown ether compounds and their application, liquid crystalline crown ether and current research were introduced briefly.2. Synthesis and characterization of amide type liquid crystalline crown ether ligandsA new kind of amide type liquid crystalline crown ether ligand was synthesized on the base of molecular design, which can be divided into two series, eight compounds according to the end alkoxy group and configuration of the compound. Series I and IICis -4,4 -bis{4 -[4 -(p-alkoxylbiphenyl)-carbonyloxy]benzamido}dibenzo-18-crown-6(10 Ⅰ) Trans-4,4 -bis{4 -{4 -(p-alkoxylbiphenyl)-carbonyloxy]benzamido}dibenzo-18-crown-6(10Ⅱ)3. Synthesis and characterization of amide type liquid crystalline crown ether complexes 10 Ⅰ A—10 Ⅰ D and 10 ⅡA—10ⅡD used as ligands, complex with K⁺ and Cu²⁺ ionrespectively, a new kind of amide type liquid crystalline crown ether complexes was therefore synthesized, which can be divided into four series, 16 complexes according to the end alkoxy group, configuration and metal ion of the compound.4. ConclusionThe synthesis procedure is optimized and improved. Some key techniques and thorny problems about the choice of solvents , the purification and separation of products are solved. The influence of end alkoxy group, configuration and complexation of the compound on the liquid crystalline behavior has been invested.The structures of the ligands and their complexes were characterizeded by means of Elemental Analysis,IR, UV-Vis, ¹H NMR, fluorescence and atomic absorption method. The polarizing optical microscopy, DSC and WAXD were applied to identify the mesophase of the compounds.Experimental results have shown that:1) Compounds 3, 5, 10and the complexes of 10 have thermotropic liquid crystal properties.2) The liquid crystal texture of all the compounds can be kept for a long time at room temperature upon quenching.3) In their liquid crystal state, all the compounds can be easily oriented in the direction ofexternal force.4) Once heated to their own melting temperature, all the ligands will go into liquid crystalphase. The typical broken fan texture and sanded texture of smectic phase can be observed. And all the complexes will also go into liquid crystal phase. The typical mosaic texture, sanded texture of smectic phase and schlieren texture, ball granul textre of nematic phase can be observed. So the nematic phase is added after complexation.5) All the complexes are nonelectrolytes, the molar conductivity is very small. It can provethat all the negative ions are compounded.And the molar conductivities of cis-configuration complexes are higher than those of trans- complexes.6) All the ligands and complexes have fluorescent properties. After complexation, the position of the emission maximum shifts to shorter wavelengths.7) For ligands and their complexes of same configuration and same series, both Tm and Tj decrease with the increase of carbon numbers in the end alkoxy group and the temperature range of smectic phase increase, whereas the temperature range of nematic phase decrease. Tm and Ti of compounds having trans-configuration are higher than those of their corresponding cw-configuration compounds.8) Tm of complexes is smaller than their ligands.But Tj of complexes of potassium are higherthan those of their ligands whereas Tj of complexes of copper are smaller than those of their ligands. And the ligands only have smatic phase but after complexation, they add nematic phase. So the liquid crystal phase length becomes broader after complexation.9) The liquid crystalline phase of ligands can be changed through complexation with metalion.